Filling means for an impact absorbing device

ABSTRACT

The single acting impact absorbing device is interposed between the underframe center sill and the sliding sill of a railway car and has a single acting cylinder housed in a square hydraulic fluid reservoir, a first head of which normally abuts stop faces on a key housing fixed to the underframe center sill and a first set of stop faces fixed to the inner walls of the sliding sill. A piston rod slidably projects through the first head and the housing and carries a movement limiting member on its outer end which normally abuts stop faces on the opposite end of the housing and a second set of stop faces on the sliding sill. A spring rod secured to the piston rod retains a spring acting between the second head and a follower at the outer end of the spring rod, the spring stressing both rods in tension. A tube adjacent the second head houses the spring and restrains it against lateral buckling in compression, and filling access to the reservoir is had through filler tubes having their lower ends opening to the outer face of the second head adjacent the spring tube. A piston fixed to the piston rod normally is held adjacent the second head, and when the railway car receives an impact it moves relatively toward the other head, expelling fluid from the cylinder into the reservoir through a decreasing number of flow restricting orifices.

Elite States Hawthorne atent 1 1 1 Dec. 3, 1974 FILLING MEANS FOR AN IMPACT ABSORBING DEVICE [75] Inventor: Vaughn T. Hawthorne,

Mechanicsburg, Pa.

[73] Assignee: Keystone Industries, Inc., Chicago,

' Ill.

22 Filed: Mar. 15, 1973 21 Appl. No.2 341,487

Related US. Application Data [60] Division of Ser. No. 191,634, Oct. 22, 1971, which is a continuation in-part of Ser. Nos. 1,903, Dec. 17, 1969, abandoned, which is a continuation of Ser. No. 710,196, March 4, 1968, abandoned.

52 us. c1. 213/43, 188/322, 267/65 R 51 int. c1. B61g 9/08 [58] Field Of Search 213/43, 8; 267/64 R, 65 R;

[56] References Cited UNITED STATES PATENTS 3,491,993 1/1970 Schohn et al. 267/64 R X 3,724,681 4/1973 Anderson et al. 213/43 3,749,255 7/1973 Cope 267/65 X Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Gene A. Church Attorney, Agent, or FirmHibben, Noyes & Bicknell [57] ABSTRACT The single acting impact absorbing device is interposed between the underframe center sill and the sliding sill of a railway car and has a single acting cylinder housed in a square hydraulic fluid reservoir, a first head of which normally abuts stop faces on a key housing fixed to the underframe center sill and a first set of stop faces fixed to the inner walls of the sliding sill. A piston rod slidably projects through the first head and the housing and carries a movement limiting member on its outer end which normally abuts stop faces on the opposite end of the housing and a second set of stop faces on the sliding sill. A spring rod secured to the piston rod retains a spring acting between the second head and a follower at the outer end of the spring rod, the spring stressing both rods in tension. A tube adjacent the second head houses the spring and restrains it against lateral buckling in compression, and filling access to the reservoir is had through filler tubes having their lower ends opening to the outer face of the second head adjacent the spring tube. A piston fixed to the piston rod normally is held adjacent the second head, and when the railway car receives an impact it moves relatively towardthe other head, expelling fluid from the cylinder into the reservoir through a decreasing number of flow restricting orifices.

9 Claims, 18 Drawing Figures swm a or s 17147111 ?ll/AI/1714wI/l/4w2MJV/l/I!!! www qmwgw t @w www :lilllllllkv l fxufllfllllll IX FILLING MEANS FOR AN IMPACT ABSORBING DEVICE CROSS REFERENCE TO RELATED APPLICATIONS This application is a division of my application Ser.

No. 191,634, filed Oct. 22, 1971, which in turn is a continuation-in-part of my copending US. application Ser. No. 1,903, filed Dec. 17, 1969 and now abandoned, which in turn is a continuation of my US. application Ser. No. 710,196, filed Mar. 4, 1968 and now abandoned.

BRIEF SUMMARY OF THE INVENTION Impact absorbing devices which are interposed between the underframe center sill structure and the sliding sill structure of a railway car must be capable of absorbing impacts received at both ends of the car. They have frequently been of the double acting type, but later designs have emphasized single acting cylinders for such devices.

It should be recognized that impact absorbing devices in order to be effective should accommodate a motion of the sliding sill within the underframe center sill of up to 20 inches. In double acting units the sliding sill travel must be accommodated for both directions within the cylinder, and this results in a substantially long unit. It also requires that the piston rod in normal condition project from the cylinder where it is customarily enclosed in a bellows. The long length of the unit claims its price in weight and extra volume of hydraulic fluid. The bellows presents a service problem because its constant flexing reduces its effective life. These units usually were filled from the top and had to be completely removed from the railway car to replenish the to be enclosed within a bellows. The piston rod acted in compression, and the external spring rubbed and wore against the walls of the sliding sill or against a guide tube. Replenishment of fluid and servicing the unit required its removal from the car.

The disadvantages and objectionable characteristics of the prior devices are overcome by the single acting impact absorbing device of the present invention which has, among others, the following advantages:

1. It requires only one stop means fixed to the underframe center sill. It is also possible to use a single stop mean s'applied'to the sliding sill, thus making possible easy installation in a railway car. The prior units require either two piston stops or two keys.

2. It is so constructed and arranged to provide tension on the operating or piston rod. Operating the piston rod in tension permits the rod to be loaded to a higher stress and eliminates alignment problems inherent in prior single acting devices.

3. It requires no oil volume compensating devices because there is equal or less displacement of oil behind the piston than in front of it. Other single acting units require some means of volume displacement.

4. It requires no bellows because the piston rod is normally within the unit. This also provides a more satisfactory condition for the lubrication of the rod as it passes through the packing.

5. It incorporates means to allow the unit to be filled while in the railway car and to protect against overfllling.

6. It provides for the accessibility of its restoring spring for service and maintenance without removing the unit from the car as is the case with other units.

7. It is so constructed and arranged that its restoring spring cannot be worn on its internal diameter. The stresses in a spring are higher on its inner section that on its outside. The spring is placed within a housing and guide tube rather than placing the tube inside the spring. This will appreciably increase spring life.

It is, therefore, the principal object of the present invention to provide a new and improved single acting impact absorbing device having the foregoing advantages over the prior art devices.

Another object is to provide a new and improved single acting impact absorbing device which is more compact, lighter in weight, and less costly to manufacture, service, and maintain than the prior devices.

Other objects and advantages will become apparent from the following description and from the drawings.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS FIG. 1 is a longitudinal sectional view through an impact absorbing device comprising a first embodiment of the present invention;

FIG. 2 is an enlarged and broken sectional view of portions of FIG. 1;

FIG. 3 is a transverse sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is an enlarged sectional view taken along the line 4-4 of FIG. 3;

FIG. 5 is an irregular transverse sectional view taken along the line 5-5 of FIG. 2;

FIG. 6 is a fragmentary sectional view taken along the line 6-6 of FIG. 5;

FIG. 7 is a schematic sectional view on the same scale as FIG. 1, showing the parts in position while moving under impact from the right;

FIG. 8 is a view similar to FIG. 7, showing the parts in position while moving under impact from the left;

FIG. 9 is a longitudinal sectional view with parts broken away, of a second embodiment of the invention;

FIG. 10 is a sectional view taken along the line l010 of FIG. 9;

FIG. 11 is a schematic sectional view on the same scale as FIG. 9, showing the parts in position while moving under impact from the left;

FIG. 12 is a view similar to FIG. 11, showing the parts in position while moving under impact from the right;

FIG. 13 is a transverse sectional view taken along the line 1313 of FIG. 9;

FIG. 14 is an enlarged and broken sectional view of portions of FIG. 10;

FIG. 15 is an enlarged sectional view taken along the line 15-15 of FIG. 14;

FIG. 16 is an enlarged sectional view taken along the line l616 of FIG. 14;

FIG. 17 is a fragmentary sectional view taken along the line l7-l7 of FIG. 16; and

FIG. 18 is a development view of a portion of the structure shown in FIG. 14.

SPECIFIC DESCRIPTION A first embodiment of an impact absorbing device of the present invention, indicated generally by the reference character 10, is shown in FIGS. 1 through 8 and is mounted between center sill structure 12 of the underframe of a railway car and sliding sill structure 14, which is housed within the center sill l2 and slides relative thereto upon impact from either end of the car. The sliding sill 14 carries at its opposite outer ends the conventional coupler and draft gear which are not shown.

As best seen in FIG. 3, both the center sill 12 and the sliding sill 14 are open at their lower sides. The center sill I2 is formed by a pair of side walls or outwardly facing wide channels 16 which are interconnected across their upper flanges by a plate 18 which forms the top portion of the center sill 12.

The sliding sill 14 comprises an inverted channel 20 which, has side walls having a pair of sidewardly projecting flanges 22 extending the length of the sill l4 and on which it slides on the various cross members of the underframe in a manner well known in the art.

The impact absorbing device 10 is housed within the sliding sill 14 but is supported on a support or frame 23 which depends from the underframe center sill 12. The frame 23 comprises a pair of longitudinally extending bars 24 which are welded to the lower faces of the lower flanges of the channels 16 and between which is mounted a subframe which includes longitudinally extending bars 26 which are secured by bolts 28 to the bars 24. Transverse angle members 30 interconnect the bars 26, and the latter are further interconnected by a plate 32 which is welded to the bars 26 and the angle members 30. To the upper surface of the plate 32 is welded a pair of pads 34 on which the flanges 22 of the sliding sill l4 slide.

Also mounted on the plate 32 is a stop means or key stop providing housing 36 which comprises a pair of elongated and spaced side walls 38 which upstand from the plate 32 and between which at their lower portions extend spacers 48. The side walls 38 are interconnected at their upper ends by a cover plate 42 bolted thereto. The side walls 38 are provided at their opposite ends, and therefore at the opposite ends of the housing, with stop face providing wear pads 44 and 45. They and the key stop housing 36 serve as the positioning unit for the impact absorbing device 10 when the sills v12 and 14 are in their normal or neutral position.

The bars 24 and 26 extend outwardly away from their position below the housing 36, and a plate 48 extends between the upper portions of these bars which are further braced by transverse members 50. The plate 48 has a wear pad 52 secured to its upper surface on which a portion of the impact absorbing device slides, as will be described hereinafter. This structure completes the impact supporting device frame 23, and it can be seen that it hangs from the center sill 12 of the underframe of the railway car.

As best seen in FIGS. 2 and 5, the impact absorbing device 10 includes a reservoir 54, rectangular, specifically square, in cross section, which is closed at its opposite ends by a first head 56 and a second and outer head 58. The opposite ends of the reservoir are welded to the heads 56 and 58 to provide a liquid tight unit.

Within the reservoir 54 is a coaxial cylinder 60 which extends between the heads 56 and 58 and is appropriately held in recesses 62 and 64 in the heads 56 and 58, respectively. It is not essential that the cylinder 60 be welded to the heads, and it is properly angularly located with respect to the reservoir 54 by a dowel 66 in the head 58. Along its length the wall of the cylinder 60 is formed with a plurality of fluid flow restricing ports or orifices 68, which communicate the interior ofthe cylinder 60 with the surrounding reservoir, and through which fluid flows during the functioning of the impact absorbing device 10, as will be explained hereinafter.

Fluid flow between the interior of cylinder 60 and the surrounding reservoir in a substantially less restricted fashion is effected by means of passages 70 formed in the head 58 and around the end of the wall of the cylinder 60 (FIGS. 5 and 6). The cylinder 60 is also formed with relatively large ports 72 at its end adjacent the head 58 for the purpose of providing further relatively unrestricted flow of fluid. These ports 72 are arranged in a position of about 22 /2 from the horizontal and vertical diameters of the cylinder as seen in FIG. 5, so that under normal conditions the passages 70 and ports 72 will be below the liquid level in the reservoir 54.

A piston 74 having a peripheral packing 76 slides within the cylinder 60, and when the relative motion of the piston 74 is to the leftwith respect to cylinder 60, as seen in FIG. 2, fluid is forced under pressure through the orifices 68 into the reservoir 54 and is taken in through the passages 70 and ports 72 and through such orifices 68 as are uncovered to the right of the piston 74. It will be observed that as the relative motion of piston and cylinder approaches the head 56 fewer flow restricting orifices 68 for the expulsion of liquid are available, and the resistance to piston movement increases as a result thereof. When the movement is in the opposite direction the passages 70 and ports 72 provide a relatively unhampered passage for the flow of fluid from the interior of the cylinder 60 to the reservoir 54,

and therefore the resistance to movement is not as great. This is important in restoring the unit to its neutral or normal position, which is that shown in FIGS. 1 and 2.

The head58 is formed with a pair of inwardly projecting bosses 78 (FIG. 6) which are drilled axially at 82 to the outer face 80 of the head 58. The outer ends of the bores 82 are normally closed by removable plugs 84. The bosses 78 are drilled radially at 86 to intercept the axial bores 82 and to receive the lower ends of upwardly extending pipes 88 which are located in the reservoir 54 adjacent the head 58. The upper and open ends 90 of the pipes 88 are adjacent the upper wall of the reservoir 54 and above most of the orifices 68 and all of the passageways 70 andports 72. When it is desired to fill the reservoir or to replenish any of the fluid which may have leaked from the reservoir 54, as will happen during normal use over a longtime period, the plugs 84 are removed and hydraulic fluid is pumped through one of the bores 82 and pipes 88 to spill into the reservoir 54. When the reservoir is filled to the desired level as measured by the open upper end 90 of the other pipe 88, hydraulic fluid will flow down the pipe and leak from the open bore 82 to signal that the reservoir is properly filled. The plugs 84 are then replaced,

and the unit will have been serviced.

The piston 74 is fixedly secured, as by welding, to an elongated member or piston rod 92 which extends outwardly through a projecting boss 94 on the head 56 to extend completely through the stop providing housing 36 as seen in FIG. 2. The piston rod is supported in the boss 94 and in the head 56 by a bushing 96 and packing 98 which is held in place by a suitable retaining ring assembly 108.

At its outer end the piston rod 92 extends through and is welded to an abutment or movement limiting member 102 which is square in transverse configuration and is provided with radial strengthening ribs 184. Because of its size and shape the member 102 is guided by the walls of the sliding sill 14 and its rotation is prevented. The piston 74 and piston rod assembly 92 are normally biased to the right as seen in the drawings, and therefore inner face 106 of the movement limiting member 182 bears against the stop faces of the pads 44 which are carried on the side walls 38 of the housing 36.

At the opposite end of the assembly of the reservoir 54 and cylinder 60 is an elongated member or a spring rod 108. The rod 188 extends through a hollow boss 110 projecting outwardly of the head 58, and at its inner end the rod 108 engages in a recess 112 in the end of the piston rod 92 and is welded thereto so that the combination of piston rod 92 and spring rod 1t18 moves as a unit. The rod 188 is supported in the head 58 by a bushing 114, packing 116, and packing retainer assembly 118.

The spring rod 188 is provided at its outer end with a spring follower 120 which is held or retained thereon by a nut 122 and a locking cotter pin 124 so that the spring follower cannot inadvertently come off the end of the rod 108. Confined between the head 58 and the spring follower 120 is a restoring means in the form of a heavy duty compression spring 126 which urges the spring follower 120 rightwardly as seen in FIGS. 1 and 2, and thus tends to hold the piston 74 in the rightward position. The motion limiting member 102 is held against the stop providing housing 36 and the assembly of the impact absorbing device is in its neutral or normal position. Since this spring is under compression, the rods 92 and 108 are stressed in tension, which permits higher stresses in the rod and requires no special structure for alignment or support.

The spring is enclosed within an elongated spring housing tube 128 which is welded in a seat in the outer face of the head 58. As seen in FIG. 6, access to the filler bores 82 and tubes 88 is at the corners of the head 58 and outside the tube 128. The spring housing tube 128 does not need any additional support, and it limits lateral buckling of the spring as it is placed under maximum compression during the absorption of an impact from either end of the railway car. This prevents wear of the spring 126 against the rod 108 and on its inner section where the stresses are higher. Circumferential wear is limited to the outside, thus giving longer spring life than was obtained heretofore. The springhousing tube is provided with an access opening 130 so that inspection may be made of the spring which otherwise cannot be seen, as during normal operation of the device the spring follower 120 never leaves the tube 128. The spring may'readily be removed from the outer and open end of the tube 128 by removing the cotter pin 124 and nut 122.

To complete the functioning of the device, the sliding sill 14 carries on its inner face two pairs of stop blocks 132 and 134. The stop blocks 132 have striking faces 136 and the blocks 134 have striking faces 138. It will be noted that the distance between the striking faces 136 and 138 is the same as the distance between the faces on the pads 44 and 46 carried at the opposite ends of the key housing 36. In normal position, therefore, of the impact absorbing device, the face 106 of the motion limiting member 102 carried on the piston rod 92 bears against the stop faces 136 and the pads 44, and the outer face of the head 56 bears against the stop faces 138 and pads 46 (FIG. 4).

The blocks 132, 134 are welded to the inner surfaces or faces of the upstanding walls of the sliding sill l4, and to increase the weld areas between the blocks and the sill, these walls are slotted at 140, there being three slots for each of the blocks 132, 134.

The functioning of the impact absorbing device can be readily appreciated from a comparison of FIGS. 1, 7 and 8. FIG. 1 shows the unit 10 in its normal position with the movement limiting member 102 bearing against the left end of the housing 36 and against the stop blocks 132. The spring 126 also urges the cylinder 60 and reservoir 54 leftwardly so that the head 56 bears against the right end of the housing 36 and against the stop blocks 134. The piston '74 is held adjacent the head 58 and the greater portion of the piston rod 92 is within the cylinder 68. Since the housing 36 is carried by the underframe sill 12 and the blocks 132, 134 are carried by the sliding sill, the sliding sill is centrally positioned within the underframe center sill 12, and the couplers and draft gear at the opposite ends of the sliding sill project normally from the car for the purpose of coupling.

Upon an impact from the right end of the car, which is illustrated in FIG. 7, the sliding sill 14 is moved leftwardly and the blocks 132 bearing against the movement limiting member 102 which is carried on the piston rod 92 forces this assembly to the left. The piston rod being fixed to the piston 74 pulls it leftwardly in the cylinder 60. Fluid is expelled from that portion of the cylinder to the left of the piston 74 through the orifices 68 and is taken into the cylinder through the passages 70, ports 72, and uncovered orifices 68. It will be noted that as the piston 74 moves progressively leftward in the cylinder 60, fewer and fewer of the ports 68 are available for the expulsion of fluid. At the end of this function the spring 126 moves the spring follower rightwardly and since it is mounted on the spring rod 108 which is fixed to the piston rod 92, the piston 74 moves rightwardly in the cylinder 60, and the movement limiting member pulls the sliding sill 14 rightwardly in the underfarme sill 12 to the normal or FIG. 1 position.

The function is similar when the impact occurs from the left end of the car and of the unit (FIG. 8). In this case the blocks 134, being in engagement with the head 56, move the assembly of the cylinder 60 and the reservoir 54 rightwardly as that the piston 74 is stationary relative to the underframe center sill 12, while the cylinder and reservoir move on the shelf plate 48 with the sliding sill 14. The motion limiting member 102 is abutted against the left end of the housing 36 and does not move relative to the underframe sill l2, and the stops 132 move away from the motion limiting member 102. Restoration is effected by the spring 126 in the same general fashion, except in this case the cylinder 60 and reservoir 54 are moved with the sliding sill 14.

A second embodiment of an impact absorbing device of the present invention, indicated generally by the reference character 210, is shown in FIGS. 9 through 18, and is mounted between center sill structure 212 and sliding sill structure 214 of a car. As best seen in FIG.

13, the center sill212 is formed by wide channels 216 and a plate 218. The sliding sill 214 comprises a channel 220 which has projecting flanges 222 on which it slides. The impact absorbing device 210 is supported on a frame 223 which comprises bars 224 welded to the channels 216. The bars 226 are secured by bolts 228 to the bars 224. Transverse angle members 230 connect to the bars 226, as does a plate 232. The plate 232 has a pair of pads 234 on which the sliding sill 214 slides.

Also mounted on the plate 232 is a key stop providing housing 236 which comprises a pair of side walls 238 and between which extend spacers 240. The side walls 238 are connected at their upper ends by a cover plate 242 and are provided at their sides or ends with stop faces providing wear pads 244 and 246 (FIG. 14). A plate 248 (FIG. 14), having braces 250 and wear plates 253 extends between the upper portions of the bars 224 and 226.

As best seen in FIGS. 13, 14, 15 and 16, the impact absorbing device 210 includes a reservoir 254 having corner reinforcements 255 (FIG. 15) and closed at its ends by a first head 256 and a second and outer head 258. Wear pads 252 are secured about the four sides of the reservoir 254. A cylinder 260 extends between the heads 256 and 258 and is appropriately held in recesses 262 (FIG. 14) and 264 in the heads 256 and 258. The cylinder 260 is angularly located by a pin 266 in the head 256. In the wall of the cylinder 260 is formed-a plurality of fluid flow restricting ports or orifices 268.

With respect to fluid flow, the embodiment 210 differs from the embodiment in that there are no passages similar to passages 70. The cylinder 260 has, instead, many large ports'272 (FIGS; 14, and 16) at its end adjacent the head 258. The ports 272 are arranged about the periphery of the cylinder. A layout of the ports 268 and 272 is shown in FIG. 18.

A piston 274 having packing 276 (FIG. 14) slides within the cylinder 260. When the piston 274 moves to the left in the cylinder 260, fluid is forced under pressure through the orifices 268 into the reservoir 254 and is taken in through the ports 272 and through such orifices 268 as are uncovered to the right of the piston 274. When the movement is in the opposite direction the ports 272 provide a relatively unhampered passage for the flow of fluid from the interior of the cylinder 260 to the reservoir 254.

The fluid filling means of the device 210 is constructed differently from that of device 10. In head 258 are openings 282 (FIGS. 16 and 17) which are located at the corners of the outer face 280 of the head 258. The outer ends of the openings 282 are normally closed by removable plugs 284. The inner ends of the openings 282 are closed by adapter plugs 283 which are welded to the head 258 and have axial openings 285 and radial openings 286. The openings 285 and 286 provide communication between the openings 282 and an upwardly extending pipe 288 which fits within the openings 286 and is located in the reservoir 254 adjacent the heads 258. The tubes 288 are pinched or squeezed, as indicated at 291, to clear the cylinder 260. To fill the reservoir 254, a similar procedure is followed as was described for device 10. A pipe plug 289 (FIG. 16) is provided for initially filling the cylinder and reservoir.

The piston 274 is fixedly secured, as by welding, to a piston rod 292 which extends at one end outwardly through a projecting boss 294 on the head 256 to extend through the housing 236, as seen in FIG. 14. The piston rod is supported by a bushing 296 and packing 298 which is retained by a ring assembly 300. The piston rod 292 is welded to a movement limitingmember 302 having strengthening ribs 304. The piston 274 and piston rod assembly 292 are normally biased to the right, and the inner face 306 (FIG. 14) of the movement limiting member 302 bears against the stop faces of the pads 244 on the side walls 238 of the housing 236.

Unlike the piston rod 92, the piston rod 292 extends through both heads of the cylinder 260, and at the other end extends through a hollow boss 310 (FIG. 14) of the head 258. A spring rod 308 at its inner end engages in a recess 312 in the other end of the piston rod 292 and is welded thereto. The rod 292 is supported in the head 258 by a bushing 314, packing 316, and packing retainer assembly 318.

Unlike the spring rod 108, the spring rod 308 is provided at its outer end with a three piece split bushing 321 which has a flange which abuts a spring follower 320. A washer 322 is welded to the end of the rod 308 and retains the bushing 321 and the spring follower 320 on the rod 308. Confined between a spring seat ring 325 adjacent the head 258 and the spring follower 320 is a heavy duty compression spring 326 which urges the spring follower 320 rightwardly as seen in FIGS. 9 and 14. Since this spring is under compression, the rods 292 and 308 are stressed in tension. The spring is enclosed within a spring housing tube 328 which is welded at one end to the spring seat 325. As seen in FIG. 16, access still is provided to the tiller bores 282. The spring housing tube 328 limits lateral buckling of the spring during the absorption of an impact from either end of the railway car. The spring housing tube may be provided with an access opening so that inspection may be made of the spring. The spring may be removed from the outer and open end of the tube 328 by compressing the spring 326 and removing the split bushing 321, the spring follower 320 then being slid over the washer 322. Then both the spring 326 and the tube 328 can be removed.

The sliding sill 214 carries a pair of one piece stop blocks 332 and 334. The stop blocks 332 and 334 have striking faces 336 at one end and striking faces 338 at the other end. It will be noted that the distance between thestriking faces 336 and 338 is the same as the distance between the faces on the pads 244 and 246 of the key housing 236. In normal position, the face 306 of the motion limiting member 302 bears against the stop faces 336 and the pads 244, and the outer face of the head 256 bears against the stop faces 338 and pads 246 (FIG. 9). The blocks 332, 334 are welded to the inner faces of the upstanding walls of the sliding sill- 214, and

to increase the weld areas between the blocks and the sill, these walls are slotted at 340 (FIG. 14), there being four slots for each of the blocks 332, 334.

The functioning of the impact absorbing device 210 is similar to that of the device 10. FIG. 9 shows the unit 210 in its normal position with the movement limiting member 302 bearing against the left end of the housing 236 and against the faces 336 of the stop blocks 332 and 334. The spring 326 also urges the cylinder 260 and reservoir 254 leftwardly so that the head 256 bears against the right end of the housing 236 and against the faces 338 of the stop blocks 332 and 334. The piston 274 is held adjacent the head 258. Since the housing 236 is carried by the underframe sill 212 and the blocks 332, 334 are carried by the sliding sill 214, the sliding sill is centrally positioned within the underframe center sill 212.

U-pon an impact from the right end of the car, which is illustrated in FIG. 12, the sliding sill 214 is moved leftwardly, and the faces 336 of the blocks 332 and 334 bearing against the movement limiting member 362 forces the piston rod 292 and the piston 274 to the left.

Fluid is expelled from that portion of the cylinder to the left of the piston 274 through the orifices 268 and is taken into the cylinder through the ports 272and uncovered orifices 268. The spring 326 returns the spring follower 320, the spring rod 303, the piston rod 292,

and the piston 274 to the right, and the movement limiting member 302 pulls the sliding sill 214 rightwardly in the underframe sill 212 to the normal or FIG. 9 position.

When the impact occurs from the left end of the car (FIG. 11), the faces 338 of the blocks 332 and 334 being in engagement with the head 256, move the cylinder 260 and the reservoir 254 rightwardly so that the piston 274 is stationary relative to the underframe center sill 212, while the cylinder and reservoir move on the shelf plate 248 with the sliding sill 214. The motion limiting member 302 is abutted against the left end of the housing 236 and does not move relative to the underframe sill 212, and the faces 336 of the blocks 332 and 334 move away from the motion limiting member 302. Restoration is effected by the spring 326 in the same general fashion, except in this case the cylinder 260 and reservoir 254 are moved with the sliding sill 214.

From the foregoing description it will be seen that the objectives which are claimed for this invention at the outset of this specification are obtained by the apparatus described.

I claim:

1. In a hydraulic cushioning unit for coaction between an underframe structure of a railway car and an elongated sliding sill structure longitudinally movable relative to the underframe structure, the improvement comprising:

a fluid reservoir.

a cylinder housed within and spaced from said reservoir,

a piston movable in said cylinder,

a pair of head members at opposite ends of said reservoir and cylinder, one of said head members being provided with a pair of openings disposed at the lower portion of the reservoir when said unit is installed in a car, removable closures in said openings, and a pair of tubes communicating with said openings and extending upwardly within said reservoir and having open upper ends disposed in the upper portion of said reservoir,

whereby said reservoir is adapted to be filled with fluid by introduction of fluid through one of said openings and its associated tube until the fluid flows out through the other of said tubes and the other of said openings.

2. The structure of claim 1 further characterized in that said reservoir and said head members have a generally rectangular cross-section and said cylinder has a generally circular cross-section, said openings being provided adjacent the lower corner portions of the head member at said opposite end of said unit and being accessible externally of the head member and being in communication with the'space between said cylinder and said reservoir.

3. In a hydraulic cushioning unit for a railway car, the

improvement comprising a fluid reservoir having a fill opening and also having an overflow opening disposed at the lower portion of the unit when the unit is installed in the car, said openings being operatively accessible when said unit is installed in said car, removable closures in said openings, and a tube communicating with said overflow opening, said tube extending upwardly within said reservoir and having an open upper end disposed in the upper portion of said reservoir at the liquid level desired in said reservoir, whereby said reservoir is adapted to be filled with liquid by the introduction of liquid through said fill opening until the liquid flows out through said tube and said overflow open- 1ng. 4. The structure of claim 3 wherein said reservoir is adapted to be only partially filled with liquid, said open end of said tube being located at the desired liquid level below the top of said reservoir.

5. The structure of claim 3, including a second tube communicating with said fill opening and extending upwardly within said reservoir, said fill opening being disposed at the lower portion of the unit'when the unit is installed in the car.

6. The structure of claim 3, wherein said unit includes a cylinder and piston assembly, said reservoir surrounding said cylinder, said tube being located in the space between said reservoir and said cylinder.

7. The structure of claim 6, including a second tube communicating with said fill opening and extending upwardly between said reservoir and said cylinder.

8. The structure of claim 7, wherein said reservoir and cylinder are closed by a pair of heads, said open ings being located in said heads.

9. The structure of claim 3, wherein said reservoir is closed by a pair of heads, said openings being located in said heads. 

1. In a hydraulic cushioning unit for coaction between an underframe structure of a railway car and an elongated sliding sill structure longitudinally movable relative to the underframe structure, the improvement comprising: a fluid reservoir, a cylinder housed within and spaced from said reservoir, a piston movable in said cylinder, a pair of head members at opposite ends of said reservoir and cylinder, one of said hEad members being provided with a pair of openings disposed at the lower portion of the reservoir when said unit is installed in a car, removable closures in said openings, and a pair of tubes communicating with said openings and extending upwardly within said reservoir and having open upper ends disposed in the upper portion of said reservoir, whereby said reservoir is adapted to be filled with fluid by introduction of fluid through one of said openings and its associated tube until the fluid flows out through the other of said tubes and the other of said openings.
 2. The structure of claim 1 further characterized in that said reservoir and said head members have a generally rectangular cross-section and said cylinder has a generally circular cross-section, said openings being provided adjacent the lower corner portions of the head member at said opposite end of said unit and being accessible externally of the head member and being in communication with the space between said cylinder and said reservoir.
 3. In a hydraulic cushioning unit for a railway car, the improvement comprising a fluid reservoir having a fill opening and also having an overflow opening disposed at the lower portion of the unit when the unit is installed in the car, said openings being operatively accessible when said unit is installed in said car, removable closures in said openings, and a tube communicating with said overflow opening, said tube extending upwardly within said reservoir and having an open upper end disposed in the upper portion of said reservoir at the liquid level desired in said reservoir, whereby said reservoir is adapted to be filled with liquid by the introduction of liquid through said fill opening until the liquid flows out through said tube and said overflow opening.
 4. The structure of claim 3 wherein said reservoir is adapted to be only partially filled with liquid, said open end of said tube being located at the desired liquid level below the top of said reservoir.
 5. The structure of claim 3, including a second tube communicating with said fill opening and extending upwardly within said reservoir, said fill opening being disposed at the lower portion of the unit when the unit is installed in the car.
 6. The structure of claim 3, wherein said unit includes a cylinder and piston assembly, said reservoir surrounding said cylinder, said tube being located in the space between said reservoir and said cylinder.
 7. The structure of claim 6, including a second tube communicating with said fill opening and extending upwardly between said reservoir and said cylinder.
 8. The structure of claim 7, wherein said reservoir and cylinder are closed by a pair of heads, said openings being located in said heads.
 9. The structure of claim 3, wherein said reservoir is closed by a pair of heads, said openings being located in said heads. 